Surgical access apparatus and method

ABSTRACT

A surgical access device is adapted for performing laparoscopic surgical procedures with multiple instruments passing through the surgical access device and through a single incision in the abdominal wall of a patient with the abdominal cavity pressurized with an insufflation gas. The surgical access device is adapted to provide instrument access to the abdominal cavity for surgical procedures while generally maintaining insufflation pressure in the abdominal cavity. The surgical access device comprises an access pad. The access pad comprises a material formed of a mixture comprising a triblock copolymer, an oil, and a foaming agent. The access pad is adapted to be disposed within an incision within an abdominal wall. The access pad has an external flange and an internal flange integrally formed with the access pad. The external flange is adapted to be disposed external to the abdominal wall in an operative position and the internal flange adapted to be disposed internal to the abdominal wall in the operative position. The access pad is configured to be maintained in the operative position and adapted to form a seal with the abdominal wall. A plurality of openings are formed through the access pad between an external surface and an internal surface of the access pad. The plurality of openings when operatively disposed are in communication with the incision and form working channels between a location external to the abdominal wall and a location internal to the abdominal wall. The access pad is adapted to conform to a surface of an instrument inserted through the working channel. At least a portion of the access pad between the external flange and the internal flange and within the incision between an external surface of the abdominal wall and an internal surface of the abdominal wall is adapted to form an instrument seal with the instrument. Locating the access pad within the incision creates a radially compressive force to provide an axial seal between the access pad and the abdominal wall.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. application Ser. No.12/360,710, filed Jan. 27, 2009, which is a continuation of U.S.application Ser. No. 11/244,647, filed Oct. 5, 2005, now U.S. Pat. No.7,481,765, which is a continuation of U.S. application Ser. No.10/381,220, filed Mar. 20, 2003, now U.S. Pat. No. 7,473,221, which isthe National Phase application under 35 U.S.C. §371 of InternationalApplication No. PCT/US2001/029682, filed Sep. 21, 2001, which publishedin English as International Publication No. WO 2002/034108 A1 on May 2,2002, which claims the benefit of U.S. Application No. 60/241,958, filedOct. 19, 2000, all of the disclosures of which are incorporated byreference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates generally to devices and other apparatusfacilitating sealed access with surgical instruments, such as asurgeon's hand, across a body wall and into a body cavity.

2. Background of the Invention

In several areas of surgery there exists a need to have mechanisms ordevices that can seal a body cavity or space, and yet permit theintroduction of surgical instruments such as guidewires, endoscopes, andeven the hand of a surgeon. Typical of these areas of surgery islaparoscopic surgery which relies on surgical instruments insertedthrough the abdominal wall to reach an operative site within theabdominal cavity. In order to increase space around the operative sitewithin the cavity, insufflation gases are typically introduced toinflate the cavity and elevate the abdominal wall. This pressurizing ofthe abdominal cavity is referred to as pneumoperitoneum. In thiscontext, the need to seal the body cavity or space arises from the needto maintain the pneumoperitoneum even when instruments are present.

Trocars have been commonly used to provide instrument access inlaparoscopic surgeries. These trocars have included elaborate sealstructures having zero seals which prevent escape of the gases in theabsence of instruments, and instrument seals which prevent escape of thegases in the presence of instruments. Unfortunately, the instrumentseals have been able to accommodate only a narrow range of instrumentdiameters. Where wider ranges were desired multiple seal pairs had to beprovided.

Some instruments, such as the hand of the surgeon, have been too largefor trocar access. Under these circumstances, hand-assisted laparoscopicseals have been provided. Such devices have been large, cumbersome, andlargely ineffective in providing the required sealing mechanism. Otheraccess devices, such as Touhy-Borst seals, have been used but only forvery small diameter access such as that required by a guidewire.

Each of the prior devices suffers from drawbacks which make the devicedifficult or cumbersome to use. For example, a Touhy-Borst seal requirestwo hands to use and does not form a seal when a guidewire or otherdevice is about to be introduced. Present trocar seals and hand-assistedseals require two valves, one forming an instrument seal in the presenceof the instrument, and the other forming a zero seal in the absence ofthe instrument. For example, in hand-assisted devices, elaboratemechanisms have been required to seal around the surgeon's arm. When thearm is removed, a separate zero seal has been required to prevent theescape of blood or insufflation gases.

SUMMARY OF THE INVENTION

These deficiencies of the prior art are overcome with the presentinvention which includes both a seal apparatus and a method for usingthis apparatus to perform elaborate surgeries. In one embodiment, thedevice includes a valve structure formed of a gel including, forexample, a thermoplastic base such as KRATON (a trademark of ShellCorporation) and an oil. The resulting elastomer has an excellent tearstrength, elongation greater than 1,000 percent, a very low durometer orhardness, and biocompatibility. A process for manufacturing this deviceis greatly simplified using molding techniques.

Importantly, the access device can function as both a zero seal and aninstrument seal. Furthermore, it can accommodate a full range ofinstrument diameters, such as a range from two French in the case of aguidewire, to three or four inches in the case of a surgeon's hand. Inaddition, several instruments can be accommodated at the same time witha single access device.

Both tear resistance and sealing capability can be enhanced byencapsulating the gel in a sheath or otherwise providing circumferentialreinforcement for the valve structure. Additives can be provided eitheron or in the gel to enhance properties such as lubricity, appearance,wound treatment and/or protection, anti-cancer protection andanti-microbial protection. Additional chemicals, compounds,pharmaceuticals or even mechanical devices can be mixed with or embeddedin the gel material to vary chemical, pharmaceutical or physicalproperties of the access device.

These and other features and advantageous of the invention will beclarified with a description of preferred embodiments and reference tothe associated drawings.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing a patient prone on an operatingtable with his abdomen insufflated, and with instrument access providedby trocars and the access device of the present invention;

FIG. 2 is an enlarged side elevation view of the access device of FIG. 1operatively disposed exteriorly as the abdominal wall;

FIG. 3 is a side elevation view similar to FIG. 2 showing the accessdevice operatively disposed interiorly of the abdominal wall;

FIG. 4 is a side elevation view similar to FIG. 2 showing the accessdevice operatively disposed within an incision in the abdominal wall;

FIG. 5 is a plan view taken along lines 5-5 of FIG. 2;

FIG. 6 is a side elevation view similar to FIG. 2 and illustrating afurther embodiment of the access device having an external flange and aninternal flange;

FIG. 7 is a side elevation view similar to FIG. 6 and illustrating thehand of a surgeon being inserted through the access device;

FIG. 8 is an axially cross section view of the access device illustratedin FIG. 6;

FIG. 9 is a cross section view similar to FIG. 8 and illustrating anembodiment with circumferential reinforcement members;

FIG. 10 is an axial cross section view similar to FIG. 9 andillustrating a double-ring retractor with an access device of thepresent invention;

FIG. 11 is a radial cross section view similar to FIG. 8 andillustrating an embodiment having a lead-in cavity or pocket;

FIG. 12 is a top plan view of the embodiment illustrated in FIG. 11;

FIG. 13 is an axial cross section view taken along lines 13-13 of FIG.12;

FIG. 14 is an axial cross section view taken along lines 14-14 of FIG.12;

FIG. 15 is an axial cross section view similar to FIG. 13 andillustrating an embodiment with a duct-bill valve;

FIG. 16 is an axial cross-section view taken along lines 16-16 of FIG.15;

FIG. 17 is a radial cross section view similar to FIG. 13 comprising asofter hand seal and a firmer base seal;

FIG. 18 is an axial cross section view taken along lines 18-18 of FIG.17;

FIG. 19 is an axial cross section view of an embodiment having a lead-incavity or pocket with a conical or funnel configuration;

FIG. 20 is a top plan view of the embodiment illustrated in FIG. 19;

FIG. 21 is an axial cross section view similar to FIG. 13 and showinganother embodiment with a trapezoidal slit;

FIG. 22 is an axial cross section view taken along lines 22-22 of FIG.21;

FIG. 23 is an axial cross section view similar to FIG. 22 taken alonglines 23-23 of FIG. 21 and illustrating a slit having other than aperpendicular relationship to the plane of the pad;

FIG. 24 is a perspective view of a further embodiment of the accessdevice having an opening formed by multiple slits angularly disposed andaxially spaced relative to each other;

FIG. 25 is a side elevation view of an access device with a slit havinga spiral configuration;

FIG. 26 is a top plan view of an access device having a spiral slit andaxial channel;

FIG. 27 is a side elevation view of an embodiment having a spiral slitand a septum seal;

FIG. 28 is an axial cross section view of a further embodiment includinga superelastic conical seal and a flexible base with annular spoke-likecams;

FIG. 29 is an axial cross section view taken along lines 29-29 of FIG.22;

FIG. 30 is an axial cross section view taken along lines 30-30 of FIG.22;

FIG. 31 is an axial cross section view similar to FIG. 28 andillustrating an embodiment including flappers;

FIG. 32 is a perspective exploded view of a further embodiment includinga gel cap, a base, and a retraction sheath;

FIG. 33 is a top plan view of the gel cap of FIG. 32;

FIG. 34 is an axial cross section view taken along lines 34-34 of FIG.33;

FIG. 35 is a top plan view of the base illustrated in FIG. 32;

FIG. 36 is an axial cross section view taken along lines 36-36 of FIG.35;

FIG. 37 is a side elevation view of the retraction sheath illustrated inFIG. 32;

FIG. 38 is a side elevation view of a further embodiment of theretraction sheath;

FIGS. 39-42 illustrate progressive steps in a preferred method of useassociated with the embodiment of FIG. 32;

FIG. 39 is a top plan view showing use of a template;

FIG. 40 is a top plan view of showing placement of the retractionsheath;

FIG. 41 is a top plan view showing placement of the base ring andsecurement of the traction sheath; and

FIG. 42 is an axial cross section view partially in section showingplacement of the gel cap relative to the base.

DESCRIPTION OF PREFERRED EMBODIMENTS AND BEST MODE OF THE INVENTION

A patient is illustrated in FIG. 1 and designated generally by thereference numeral 10. The patient 10 is shown in a prone position on anoperating table 12, where abdominal surgery is being performed by asurgeon 14 having an arm 16 and a hand 17. In the illustrated example,the operative procedure is performed within an abdominal cavity 18 withinstrument access provided through an abdominal wall 21. In this type ofoperation, commonly referred to as laparoscopic surgery, trocars 23 and25 are commonly used to provide minimally invasive access through theabdominal wall 21 for instruments such as a grasper 27 and an endoscope30

Although the specific focus of this disclosure will be on a preferredlaparoscopic procedure, it will be noted that laparoscopic surgery ismerely representative of a type of operation wherein a procedure can beperformed in a body cavity with minimal access through a body wall.

Notwithstanding the foregoing generality, it is important to note thatwith respect to laparoscopic surgery, it is often desirable that thesurgeon 14 be able to insert his/her hand 17 through the abdominal wall21 and into the abdominal cavity 18. This insertion of the hand 17provides the surgeon 14 with direct access to various elements of theanatomy

In order to accommodate the hand 17 and arm 16 of the surgeon 14, asmall incision 32 is typically created in the abdominal wall 21. Anaccess device 34 of the present invention can be provided to furtherfacilitate this access by the hand of the surgeon 14.

Particularly in the case of laparoscopic surgery, it is advantageous toinsufflate the abdominal cavity 18 with a gas, such as carbon dioxide,in order to elevate the abdominal wall 21 and thereby increase thevolume of the working space within the cavity 18. Maintenance of thisinsufflation pressure, commonly referred to as pneumoperitoneum, isparticularly difficult where access is desired across the abdominal wall21, for example, through the trocars 23, 25, as well as the accessdevice 34. For this reason, a substantial effort has been directed toproviding such access devices with sealing characteristics both in thepresence of instruments and in the absence of instruments, such as thegrasper 29, scope 30 and hand 27.

Thus, the trocars 23 and 25 have typically been provided with complexvalve structures, including, for each narrow range of instrument sizes,an instrument valve which forms an instrument seal in the presence of aninstrument, and a zero valve which forms a zero seal in the absence ofan instrument. By providing both an instrument seal and a zero seal thevalve structures have been able to inhibit the escape of gases throughthe trocars both in the presence and the absence of an instrument,respectively.

The instrument seals have been particularly cumbersome, as noted, andhave only been effective for a small range of instrument diameters. Forexample, separate instrument seals have been needed for instruments,such as guidewires, which may have a diameter of only two French tothree French. For medium-sized instruments having diameters of threemillimeter to five millimeters, a second instrument seal has beenrequired. In some cases, even a third instrument seal has been necessaryin order to accommodate instruments having diameters such as ninemillimeters to 12 millimeters.

Typically the varying sizes of instruments have also required individualzero seals for each range. Thus, in a complex trocar, such as the trocar23, there might be as many as six separate seals associated with theaccess device.

Were it not for the desire to maintain the pneumoperitoneum, there wouldbe no need for the trocars 23, 25 or the access device 34. One wouldmerely cut an incision in the abdominal wall 21 and insert theinstrument directly through the incision. However, without appropriatevalves or seals, the insufflation gases would merely escape through theincisions. This would be particularly detrimental in the case of theincision 32 which must be sufficiently large to accept the hand 17 ofthe surgeon 14. Thus it is a primary purpose of the access device 34 toform with the incision 32 an access or working channel 34, and toprovide a valve or other sealing structure across the working channel 34in order to maintain the pneumoperitoneum.

An enlarged view of one embodiment of the access device 34 isillustrated in FIG. 2 which also shows the abdominal wall 21 and theincision 32. In this simple form, the access device 34 has the generalconfiguration of a pad 35, meaning that it is generally flat anddisposed in a plane such as the plane 38. Typically parallel to thisplane 38 are a pair of major surfaces of 41 and 43 which provide the pad35 with a substantial surface area. An opening or slit 45 can be formedthrough the pad 35, generally along an axis 47 perpendicular to theplane 38.

When operatively disposed, the opening 45 of the pad 35 is incommunication with the incision 32 and, in this case, forms with theincision 32, the working channel 36. The alignment of the opening 45 andincision 32 can occur with the pad 35 disposed exteriorly of theabdominal wall as illustrated in FIG. 2, interiorly of the abdominalwall is 21 as illustrated in FIG. 3, or within the abdominal wall 21 asillustrated in FIG. 4. In any of these positions, operative dispositionof the pad 35 relative to the abdominal wall 21 requires that the pad 35be maintained in its operative position and that it form a seal aroundthe incision 32. Referring to the plan view of FIG. 5, these twofunctions are accomplished with an adhesive 50 disposed around theincision 32 between the pad 35 and the abdominal wall 21.

If this adhesive 50 is formed as a continuous ring 52, as illustrated inFIG. 5, the pad 35 can be disposed with the ring 52 positionedcircumferentially around the incision 32 to form a seal between the pad35 and the abdominal wall 21. In the illustrated example, when the pad35 is operatively positioned, the escape of insufflation gases isinhibited between the pad 35 and the abdominal wall 21 by the adhesivering 52.

The escape of insufflation gases is inhibited through the opening 45 ofthe pad 35 by the self-sealing characteristics of the material formingthe pad 35. This material and its highly advantageous properties arediscussed in significant detail below.

It will be appreciated that the functions of the adhesive ring 52 can beaccomplished in many different ways using many different materials andshapes. For example, many materials other than adhesives can be used tomaintain the pad 35 in position over the incision 32. The formation of aseal around the incision 32 can also be accomplished with methods otherthan adhesion. Furthermore, the shape of the continuous seal formed bythe adhesive 50 need not be in the shape of a circle. Rather, anycontinuous pattern sufficiently large to form a perimeter around theincision 32 could facilitate the desired sealing relationship. Finally,it will be noted that the mere placement of the pad 35, for example,interiorly of the abdominal wall 21 as illustrated in FIG. 3, mayproduce a perimeter seal merely as a result of the insufflationpressure.

A further embodiment of the access device 32 is illustrated in FIG. 6where elements of structure similar to those previously disclosed ordesignated with the same reference numeral followed by the lower case“a.” In this embodiment, the functions of position-maintenance andsealing are accomplished with an alternative configuration for theaccess device itself. The pad 35 in this case is disposed within theincision 32 as illustrated in FIG. 4. However, an external flange 54 andan internal flange 56 are formed integral with the pad 35.

When operatively disposed, the external flange 54 is positioned outsideof the abdominal wall 21 while the internal flange 56 is disposedinteriorly of the abdominal wall 21 a. In this matter, the pad 35 can bedisposed within the incision 32 a and held in position by the flanges54, 56. When the hand 17 of the surgeon 14 is inserted through theaccess device 34, the exterior flange 54 prevents the pad 35 a frommoving distally. Similarly, when the hand 17 of the surgeon 14 iswithdrawn, the interior flange 56 prevents the pad 35 a from movingproximally

In this embodiment, the opening 45 a extends through the pad 35 a aswell as the flanges 54 and 56, and completely defines the workingchannel 34 through the incision 32.

The primary seal which is required between the access device 34 a andthe abdominal wall 21, can be formed with the adhesive ring 52 a asdiscussed with reference to FIG. 6. Alternatively, this embodimentincluding the interior flange 56 may rely merely upon the surfacecontact between the flange 56 a and the abdominal wall 21. In this case,the primary seal can be formed between these structural elements andenhanced by the pneumoperitoneum pressure which forces the interiorflange 56 against the abdominal wall as illustrated by a plurality ofarrows 58. This seal is formed primarily in a radial plan generallyperpendicular to the axis 47.

The function of the primary seal may be further enhanced by additionalsealing which occurs between the pad 35 a and the portions of theabdominal wall 21 forming the incision 32. In this location, theabdominal wall 21 is radially compressed by the mere presence of the pad35 within the incision 32. The resulting pressure produces an axial sealbetween the pad 35 a and the abdominal wall 21.

If the adhesive ring 52 a is desired for this embodiment, it is mostadvantageously placed around the incision 32, between the exteriorflange 54 and the abdominal wall 21.

It will be noted that whenever an instrument, such as the arm 16 or hand17 of the surgeon 14, is inserted through the pad 35, the material ofthe pad conforms to the surface of the instrument and forms theinstrument seal with the instrument. Accordingly, during the entireperiod beginning with insertion of the instrument and ending withwithdrawal of the instrument, there is substantially no loss ofinsufflation gas through the pad 35 a nor any loss of pneumoperitoneumwithin the abdominal cavity 18.

With further reference to FIG. 7, it will be appreciated that the arm 16and hand 17 of the surgeon 14 are merely examples of instruments whichcan be inserted through the access device 34 a. In the absence of theinstrument, or hand 17 in the case of FIG. 7, the opening or slit 45 amerely closes against itself to form a zero seal, thus preventing theescape of insufflation gases through the access device 34 a. When theinstrument, such as the hand 17, is inserted through the opening or slit45 a, an instrument seal is formed between the material of the accessdevice 34 a and the exterior surface of the instrument. This preventsthe escape of insufflation gases through the access device 34 a, evenwhen an instrument is present. Thus, insufflation pressures can bemaintained within the abdominal cavity 18 whether or not the instrumentis in place. Note that these seals, the zero seal and the abdominalseal, can be formed as a single valve structure having properties foraccommodating a full range of instrument sizes.

Formation of the pad 35 a will typically be accomplished in a simplemolding process described in greater detail below. In such a process,the opening or slit 45 a may be formed as part of the molding process.

In most cases, the single access opening 45 a will be sufficient toaccommodate the operative procedure. However, a further advantage of theaccess device 34 a will be particularly appreciated by the surgeon 14who requires even more access through the pad 35 a. Consider forexample, the surgeon 14 having his/her arm 16 inserted through theopening 45 a when he/she decides that a further instrument is requiredfor the operative procedure. Under these circumstances, a furtheropening through the pad 35 a can be established by merely inserting thedesired operative instrument through the pad 35 a. In this manner, theinstrument can create its own access hole beside the primary opening 45a.

Particularly for those operative instruments having pointed distal ends,the instrument can merely be forced through the pad 35 a forming its ownaccess hole, such as the opening 45 a, as it is moved distally. Thisopening, created by the operative instrument itself, would automaticallyform an instrument seal as the instrument is inserted, as well as a zeroseal as the instrument is withdrawn.

For operative instruments not having pointed distal ends, it is possibleto form a new access hole using a secondary instrument, such as a trocarobturator. After the access hole is formed, the obturator can beremoved, vacating the access hole to receive the operative instrument.Throughout this process of initially forming an access hole andultimately inserting an operative instrument through the hole, both zeroseals and instrument seals are formed to maintain the pneumoperitoneum.

With the advantages associated with 1) the formation of an instrumentseal and a zero seal with a single valve accommodating a wide range ofdiameters, and 2) the formation of an instrument opening using theinstrument itself, it will be appreciated that the concept of thisinvention will typically be embodied with a structure that isparticularly dependent upon the material which forms the access device34. In a preferred embodiment, the pad 35 is formed of a KRATON/oilmixture including a KRATON Tri-block with aStyrene-Ethylene/Butylene-Styrene (S-E/B-S) structure in combinationwith a mineral oil. Other tri-block polymers can be used for thisapplication such as Styrene-Isoprene-Styrene, (S-I-S),Styrene-Butadiene-Styrene (S-B-S), Styrene-Ethylene/Propylene-Styrene(S-E/P-S) manufactured under the trademark SEPTON by the Kuraray Co.These general formulas can be further distinguished by the ratio of thestyrene to rubber content: for example, Grade 1650 is a S-E/B-Stri-block with a 29/71 styrene to rubber ratio.

In addition to tri-blocks there are also di-block versions of thesematerials where styrene is present at only one end of the formula, forexample, Styrene-Ethylene/Butylene (S-EB) di-block.

The various base formulas may also be alloyed with one another toachieve a variety of intermediate properties. For example KRATON G1701Xis a 70% S-EB 30% S-E/B-S mixture with an overall Styrene to rubberratio of 28/72. It can be appreciated that an almost infinite number ofcombinations, alloys, and Styrene to rubber ratios can be formulated,each capable of providing advantages to a particular embodiment of theinvention. These advantages will typically include low durometer, highelongation, and good tear strength.

It is contemplated that the material of the pad 35 may also includesilicone, soft urethanes and even harder plastics which might providethe desired sealing qualities with the addition of a foaming agent. Thesilicone materials can be of the types currently used for electronicencapsulation. The harder plastics may include PVC, Isoprene, KRATONneat, and other KRATON/oil mixtures. In the KRATON/oil mixture, forexample, oils such as vegetable oils, petroleum oils and silicone oilsmight be substituted for the mineral oil. In the broadest sense, all ofthese mixtures can be described generally as a gel. The gel willtypically have properties including an ability to “flow” whichapproaches that of a fluid. Particularly in the vicinity of any openingor slit 45 extending through the access device 34, propagation of theopening may be of concern. Stresses resulting from the presence of aninstrument will be concentrated at the ends of such an opening or slit.For this reason, a good tear resistance is desired for the gel material.Such a tear resistance is often inherent in the KRATON/oil mixtures andmay be enhanced by encapsulating the gel in other materials. Forexample, a low tear resistant gel could be encapsulated in a urethanesheath to improve the tear resistant qualities of the resultingproducts. Such a sheath need not be elastic but could be comprised, forexample, of overlapping sheets of a non-elastic material.

Any of the gel materials contemplated could be modified to achievedifferent properties such as enhanced lubricity, appearance, and woundprotection, or to provide anti-cancer or anti-microbial activity.Additives can be incorporated directly into the gel, for example in thecase of pharmaceuticals, or applied as a surface treatment to the gel,for example, to improve lubricity or appearance. Other compounds couldbe added to the gel to modify its physical properties or to assist insubsequent modification of the surface by providing bonding sites or asurface charge. Antioxidants and antirads can be added to the mixture toextend the shelf life of the finished product or increase its ability towithstand radiation sterilization.

Sealing materials used in medical access devices of the past have beenchosen primarily for their durometer and elongation. It is theseproperties which measure the ability of the material to move into smallspaces and crevices as may be required to form an instrument seal acrossthe working channel of a trocar. For example, in the past, a siliconemixture was used in medical valves. This mixture had the followingproperties: an ultimate elongation less than about 1000 percent and adurometer not less than about 5 Shore A.

These properties of the prior art materials are far exceeded by theproperties associated with the present invention which in some respectsprovide a full magnitude of advantage. In fact, the difference betweenthe materials of the prior art and the materials of the presentinvention are sufficiently substantial, that it is perhaps misleading torefer to the present material as merely a gel. According, the materialof the present invention, having properties including an ultimateelongation greater than about 1000 percent and a durometer less thanabout 5 Shore A, will be referred to herein as an “ultragel.”

In a preferred embodiment of the present invention, the ultragelincludes KRATON and mineral oil and provides a sealing material with thefollowing properties: an ultimate elongation exceeding about 1500percent, and a durometer of less than about 200 Bloom. The durometer inthis case is considerably lower than that of the prior art materials. Infact, the durometer of the present material is so soft it cannot even bemeasured on the Shore A scale.

The resulting elongation and durometer of the present materialfacilitates its use with as an access valve which is capable of formingseals with a full range of instrument sizes, but is also capable offunctioning as a zero seal. Whereas access devices of the prior art mayhave required as many as six separate seals in order to accommodate afull range of instrument sizes, access devices can now be made with onlya single valve formed of the ultragel material.

In a typical manufacturing process, the KRATON G1651 is mixed with themineral oil in a ratio by weight of 1 to 9. In order to manufacture thismaterial, the combination is heated to a temperature of about 200°centigrade. In a preferred method of manufacturing, the mold is providedwith a circumferential ring insert which is molded into the gel, andslit inserts which can be removed from the gel to form the opening orslit 45. The resulting gel can be coated with cornstarch to reduce tackand cooled at room temperature.

Many of the properties of the KRATON/oil mixture will vary withadjustments in the weight ratio of the components. In general, thegreater the percentage of mineral oil, the more fluid the mixture; thegreater the percentage of KRATON, the more rigid the material. Weightratios of KRATON to oil as low as 1 to 5 have been contemplated for amore rigid structure. As the KRATON/oil weight ratio approaches 1 to 10,the mixture becomes more liquid. Ratios as high as 1 to 15 have beencontemplated for this invention.

The processing temperature can also vary considerably as it is primarilydependent on the type of KRATON used. Temperatures in a range of about150° centigrade to about 250° centigrade have been contemplated.

With an appreciation that these ratios and temperatures can developconsiderably different properties, it is now apparent that thesematerials can be layered to provide generally different propertieswithin each layer. For example, an outer layer might be formed of aKRATON/oil mixture having more rigid properties, thereby providing thepad 35 with an outer layer that is more rigid. After that layer is atleast partially cured, another layer of the material can be pouredinside of the outer layer. This second layer might be softer providingthe pad 35 with the significant sealing properties. It has been foundthat successive layers will tend to fuse slightly at their interface,but will generally maintain their separate identities. Additional layerscould be added to provide a progression of properties in a particulardevice.

Having discussed the properties desirable for the gel material, and theprocess of manufacture, one can now address the other embodiments of theconcept which may provide additional advantages for particular surgicalprocedures. An embodiment of the access device 34, shown in itsoperative position in FIG. 6, is illustrated by itself in the axialcross section view of FIG. 8.

This same embodiment can be reinforced with o-rings 61 and 63 asillustrated in FIG. 9 where elements of structure are designated by thesame reference number followed by the lower case letter “b.” Providingthese o-rings 61 and 63 may facilitate several functions associated withthe access device 34 b. For example, the rings 61, 63 will typically aidin maintaining a radial sealing pressure on all sides of the opening 45b. The rings 61 and 63 will also tend to maintain the flanges 54 b and56 b respectively, in their generally planar configurations. Thisfurther ensures that the flanges 54, 56 will not collapse into theincision 32 with the insertion or withdrawal of an instrument, such asthe surgeon's hand 17. Of course, the o-rings 61 and 63 must besufficiently large to accommodate the instrument during insertion andremoval.

A further embodiment of the invention is illustrated in FIG. 10, whereelements of structure are similar to those previously disclosed aredesignated with the same reference numerals followed by the lower caseletter “c.” This embodiment includes the pad 35 c with the opening orslit 45 c. The external perimeter o-ring 61 c is inserted molded intothe circumference of the pad 35 c. The internal o-ring 63 c is coupledto the pad 35 c, for example, by way of attachment to the o-ring 61 cfor example, by a membrane 65. In this case, the membrane 65 has agenerally cylindrical configuration and elastomeric properties. Inpreferred embodiments, the membrane 65 is formed of urethane, neopreneor isoprene.

When the embodiment of FIG. 10 is being operatively positioned, theinternal o-ring 63 b is initially gathered and inserted through theincision 32 (FIG. 2). The pad 35 c and external o-ring 61 c are leftoutside the incision 32 so that the only material extending across theincision 32 is the membrane 65. It will be noted that in this case, theworking channel 36 c is formed by the slit 45 c, the cylindricalmembrane 65, and the internal o-ring 63 b.

In this particular embodiment, the pad 35 c functions generally asdescribed with reference to FIG. 2. The primary seal between the pad 35c and the abdominal wall 21 can be formed either with a circumferentialring, such as the adhesive ring 52 c, or by relying on the sealingcharacteristics of the insufflation gas against the internal o-ring 63 band membrane 65.

This embodiment of FIG. 10 is of particular advantage as it incorporatesthe pad 35 c in perhaps its simplest configuration, while providing aprimary seal between the device 34 c and the abdominal wall 21 which isfacilitated by the insufflation pressure. Furthermore, the membrane 65enhances the sealing characteristics of the device 34 c, and provides alining for the incision 32. With the membrane 65, the incision 32 neednot be stretched to a diameter greater than that required by anyinstrument inserted through the working channel 36 c.

A further embodiment of the invention is illustrated in FIG. 11 whereelements of structure similar to those previously disclosed aredesignated with the same reference numeral followed by the lower caseletter “d.” This embodiment is similar to that of FIG. 8 in that itincludes the pad 35 b, slit 45 d, exterior flange 54 d, and internalflange 56 d. The embodiment of FIG. 11 differs from that of FIG. 8 inthat it includes a lead-in cavity 70 which is in communication with theslit 45 d.

In a preferred embodiment, this cavity 70 is sized and configured toreceive the arm 16 of the surgeon 14 in a manner illustrated in FIG. 7.In this case, the slit 45 d would function primarily to maintain a zeroseal, while the portions of the pad 35 d or flange 54 d which form thecavity 70 would function primarily to form the instrument seal.

A further embodiment of the invention is illustrated in the plan view ofFIG. 12 and the cross section views of FIGS. 13 and 14. In thisembodiment, elements of structure similar to those previously discussedare designated with the same reference numeral followed by the lowercase letter “e.” In this case, the lead-in cavity has the general shapeof a cylinder 72 with an axis that is collinear with the axis 47 e ofthe pad 35 e.

As perhaps best illustrated in FIG. 13, the slit 45 e has a trapezoidalconfiguration. Thus, it begins proximally with a narrow length which maygenerally be equivalent to the diameter of the cylinder 32. From thecavity 70 e, the length of the slit 45 e increases with progressivepositions distally through the pad 35 e. In the illustrated embodiment,the trapezoidal slit 45 e is formed as the frustum of an isoscelestriangle.

A further embodiment of the invention is illustrated in FIGS. 15 and 16wherein elements of structure similar to those previously described aredesignated with the same reference numeral followed by the lower caseletter “f.” As previously discussed with reference to FIG. 12, thisembodiment of the pad 35 f is formed with a proximal surface 71 and adistal surface 73. The pad 35 f also includes the coaxial lead-incylinder 72 f and the trapezoidal slit 45 f. However, in this case, aduck-bill valve 74 is provided to further enhance the characteristics ofthe zero zeal. As illustrated, the working channel 36 f is formed by thelead-in cavity 70 f, the slit 45 f, and an extension of the slit 45 fwhich is defined by the duck-bill valve 74 f.

The duck-bill valve 72 can be formed with opposing flanges 76 and 78which extend distally of the distal surface 73. When operativelydisposed, the pad 35 f can be positioned with its distal surface 73against the exterior surface of the abdominal wall 21 (FIG. 2) and withthe flanges 76 and 78 extending into the incision 32. With thisconfiguration and operative disposition, the abdominal wall 21 at theincision 32 will produce opposing forces on the flanges 76 and 78 whichtend to close the slit 45 f, particularly in the absence of aninstrument. In this manner, the duck-bill valve 74 can be relied on toenhance the characteristics of the zero seal.

A further embodiment of the invention is illustrated in FIGS. 17 and 18wherein elements of structure similar to those previously discussed aredesignated by the same reference numeral followed by the lower caseletter “g.” In this embodiment of the access device 34 g, the pad 35 gcan be formed generally as discussed with reference to FIG. 13. In thisembodiment, however, the pad 35 g can be enclosed along its sides andthe distal surface 73 g, by a base 81. In this case, the pad 35 g mightbe formed by the highly elastic material previously discussed, while thebase 81 might be formed of a more rigid but nevertheless flexiblematerial such as a urethane. With this configuration, the duck-billvalve 74 f would be structured to extend distally of a distal surface 83associated with the base 81. This would enable the duck-bill valve 74 fto be formed of the base material rather than the superelastic material.This might also improve the zero seal characteristics for particularoperative applications.

Another simplified form of the invention is illustrated in FIGS. 19 and20, where elements of structure similar to those previously discussed ordesignated with the same reference numeral followed by the lower caseletter “h.” The lead-in cavity 78 h, in this case, is formed as aninverted cone 77 having its base at the proximal surface 71 h and itsapex in proximity to the distal surface 73 h. Thus, the lead-in cavity70 h has an area in radial cross section which decreases withprogressive positions distally through the pad 35 h. In this embodiment,the proximal regions near the base of the cone 87 form the instrumentseal, while the distal regions at the apex of the cone form the zeroseal. The conical configuration of the lead-in cavity 70 h also tends tofunnel an instrument into the opening 45 h leading distally to the apexof the cone 87.

It will be appreciated generally, that the slit 45 and lead-in cavity 70can be provided with many different individual and cooperativeconfigurations. By way of example, perhaps the simplest form for the pad35 is illustrated in the embodiment of FIGS. 21 and 22 wherein elementsof structure similar to those previously described are designated by thesame reference numeral followed by the lower case letter “j.” In thisembodiment, the pad 35 j with its proximal surface 71 j and distalsurface 73 j, is provided with a simple trapezoidal slit 45 j. In thiscase, the slit 45 j extends between the proximal surface 71 j and thedistal surface 73 j.

The slit 45 j in this embodiment of FIG. 21 is typical of manystructures which will define the slit 45 j with a planar configuration.In such a case, the portions of the pad 35 j which form the slit willcomprise opposing planar surfaces such as those designated by thereference numerals 90 and 92 in FIG. 22.

It will be apparent that the slit 45 need not be formed by opposingsurfaces having a planar configuration. Nevertheless, these opposingsurfaces need to be capable of coming into sealing contact with eachother in order to establish the zero seal. Other slit configurationscapable of accomplishing this function, may offer further advantages inparticular procedures. Other examples of slit configurations areillustrated merely by way of example in FIGS. 23-26.

The embodiment of FIG. 23 is similar to that of FIG. 22 in that theopening 45 j comprises a single slit which extends from the proximalsurface 71 j to the distal surface 73 j. In the case of the FIG. 22embodiment, the axis 47 j is disposed within the plane of the slit 45 j.In the case of the FIG. 23 embodiment, the plane of the slit 45 j doesnot include the axis 47 j. Rather, the slit 45 j is formed in a planewhich has an angular relationship with the axis 47 j, the proximalsurface 71 j, as well as the distal surface 73 j. This constructionenables the slit 45 j to have a length greater than the thickness of thepad 35 j.

In the embodiment of FIG. 24, elements of structure similar to thosepreviously discussed are designated with the same reference numeralfollowed by the lower case letter “k.” In this case, the opening 45 k isconfigured as two slits 94 and 96 formed in individual planes that areangularly spaced with respect to each other. Of course, two or more ofthe planar slits 94 and 96 may be equally angularly spaced around theaxis 47 k. In one embodiment, the individual planar slits 94 and 96intersect at the axis 47 k. Alternatively, the slits 94 and 96 may beaxially spaced in order to facilitate formation of the instrument seal.

In the embodiment of FIG. 25, elements of structure similar to thosepreviously discussed are designated with the same reference numeralfollowed by the lower case letter “m.” In this embodiment, the opening45 m is defined as a slit 98 having a curved rather than planarconfiguration. In the illustrated embodiment, the curved slit 98 isformed as a spiral around the axis 47 m. Along the axis 47 m, theopposing surfaces forming the spiral slit 98 can “flow” into sealingproximity in order to produce the zero seal.

FIG. 26 illustrates a similar embodiment including a spiral slit. Inthis figure, elements of structure similar to those previously discussedare designated by the same reference numeral followed by the lower caseletter “n.” The spiral slit 98 n in this embodiment is also formedaround the axis 47 n of the pad 35 n, but in this case the portionsforming the slit 98 n do not extend completely to the axis 47 n. As aresult, an axial channel 100 is formed at least partially along the axis47 n. This channel 100 can function in a manner similar to the lead-incavity 70 discussed with reference to FIGS. 11-12. This channel 100 caneven be formed with a conical configuration similar to that discussedwith reference to FIG. 19.

In an embodiment where the channel 100 is left open, a zero seal mightbe provided by positioning a septum valve across the channel 100. Suchan embodiment is illustrated in FIG. 27, wherein the septum valve isdesignated with a reference numeral 101 and the other elements ofstructure similar to those previously discussed are designated with thesame reference numerals followed by the lower case letter “p.” Thus theembodiment of FIG. 27 includes the spiral slit 98 p, the pad 35 p, andthe axis 4′7 p. This embodiment of FIG. 27 is merely representative ofmany other embodiments that will combine a slit, such as the slit 98 p,with other valve structures, such as the septum valve 101.

Other curved slit configurations would include embodiments wherein theslit is curved, sinusoidal, or S-shaped in a side elevation view. Suchconfigurations provide a slit part having a length greater than thethickness of the pad. Normally, the more circuitous the slit path, thebetter the sealing characteristics.

A further and more complex configuration for the opening 45 isillustrated in the embodiment of FIG. 28 wherein elements of structuresimilar to those previously disclosed are designated with the samereference numeral followed by the lower case letter “q.” This embodimentis representative of many other complex embodiments which can be formedwith intricate shapes and different materials in order to accomplish thedesirable function of forming, with a single valve, a zero seal as wellas an instrument capable of accommodating a full range of instrumentsizes. In the embodiment of FIG. 28, the pad 35 q is formed with a base110 which is disposed circumferentially of a core 112. In this case, thecore 112 is formed of the superelastic material or gel and provided withthe shape of the cone 87 q as discussed with reference to FIGS. 19 and20. The base 110 is formed from a material that may not be elastic, butpreferably is flexible. In the preferred embodiment, the base 110 isformed of a urethane.

In this construction, the base 110 is provided with a plurality ofspokes 114 each of which extends radially inwardly from a base 116 to atip 118. The core 112 extends from the axis 47 q outwardly to the tips118 of the spokes 114. In the illustrated embodiment, the core 112 hasfingers 121 which extend beyond the tips 118 and toward the bases 116between each adjacent pair of the spokes 114. These fingers 121 extendradially outwardly to an end surface 123 which stops short of the base116 leaving a void 125 therebetween.

The voids 125 are of particular interest to this embodiment and can beincorporated into any of the embodiments previously discussed. Suchvoids 125 provide a space or absence of material into which the highlyelastic material, such as that of the fingers 121, can expand duringinsertion of an instrument such as the arm 16 (FIG. 7). Since the gelmaterial is almost fluid in its properties, the voids 125 permitexpansion of the gel with very little resistance. Voids, such as thevoids 125 in the embodiment of FIG. 28, can be defined solely in the gelmaterial or between the gel material and any other base material.

In the case of FIG. 28, the spokes 114 and fingers 121 are definedgenerally in planes which are parallel to the axis 47 q. Similarfingers, illustrated in the embodiment of FIG. 31 are defined generallyin a plane which is perpendicular to the axis. In this embodiment,elements of structure similar to those previously disclosed aredesignated by the same reference numeral followed by the lower caseletter “r.” As illustrated, the pad 35 r can be formed with a relativelylarge opening 45 r having the configuration of a coaxial cylinder 130. Aplurality of fingers or flaps 132 extend into the opening 45 r and tendto form a lead-in cavity 70 r with properties such as those discussedwith reference to FIG. 19. In this case, the annular flaps 132 have aconical configuration extending from a base 134 to an apex 136. It willbe noted that the areas between the flaps 132, form voids 125 r intowhich the flaps 132 can be displaced upon insertion of an instrument,such as the arm 16.

A further embodiment of the invention is illustrated in FIG. 32 whereelements of structure similar to those previously disclosed aredesignated with the same reference numeral followed by the lower caseletter “s.” This exploded view of the access device 34 s includes notonly the pad 35 s but also a complimentary structure for maintaining theposition of the pad 35 s, for forming a seal between the pad 35 s andthe abdominal wall 21, and for dilating the incision 32 to a variableextent as required by the surgeon 14. In this case, the access device 34s includes three components, a gel cap 143, base 145, and a retractionsheath 147.

The gel cap 143 includes not only the gel pad 35 s, but also acircumferential cap ring 154 which can be inserted and molded to the pad35 s. The resulting gel cap 143 forms a seal with the base 145, therebydefining the working channel 36 s through the pad 35 s, the cap ring154, the base 145, and the retraction sheath 147. In the mannerpreviously discussed, this working channel 36 s includes the singlevalve formed by the gel pad 35 s which provides both a zero seal and aninstrument seal for a wide range of instrument diameters.

The structure associated with the gel cap 143 is described in greaterdetail with reference to FIGS. 33 and 34. In the plan view of FIG. 33,it can be seen that this embodiment includes the gel pad 35 s centrallydisposed within the circumferential cap ring 154. Holding tabs 156 canbe provided to extend radially outwardly of the cap ring 154. Theseholding tabs 156 can facilitate the sealing engagement of the gel cap143 with the base 145 in the manner described in greater detail below.

The gel pad 35 s can be formed of any of the materials previouslydiscussed although the preferred embodiment includes the KRATON/mineraloil gel. The cap ring 154 for such an embodiment can be advantageouslyformed of KRATON only. This will make the cap ring 154 more rigid thanthe gel pad 35 s while maintaining an excellent material interfacebetween the pad 35 s and the ring 154. In a typical manufacturingoperation, the cap ring will be pre-disposed in the mold for the gel pad35 s with the unitary structure of the gel cap 143 resulting.

The cross section view of FIG. 34 shows the gel cap 143 s andillustrates an annular void 158 formed on the inner circumference of thecap ring 154. This void 158 is of particular advantage in forming asealing relationship with the base 145 in the manner discussed ingreater detail below.

The base 145 of this embodiment is shown in greater detail in the planand cross section of views of FIGS. 34 and 35, respectively. From theseviews it will be noted that the base 145 can be provided with a smoothgenerally cylindrical inner surface 161 which extends proximally to arounded end surface 163 and outwardly from the end surface 163 along anannular lip 165. A plurality of tabs 167 can be equally spaced to extendoutwardly and distally around the circumference of the lip 165.

Distally of the inner surface 163, an annular flange 170 can be providedwith an annular projection 172 sized and configured to form the desiredsealing relationship between the gel cap 143 and the base 145. Theprocess of molding the base 145 can be facilitated by forming the baseas two separate components divided, for example, by a dotted line 174 inFIG. 35. In a preferred embodiment, the base 145 is molded from apolycarbonate material.

A preferred embodiment of the retracting sheath 147 is illustrated inFIG. 37. In this view it can be seen that the retraction sheath 147includes a tubular wall 175 which has the configuration of the frustumof a cone 176 at its distal end and the configuration of a cylinder 177at its proximal end. A flexible retaining ring 152 terminates the distalend while a fold 154 is formed at the proximal end. The tubular wall 175is illustrated to include an outer surface 180 and an inner surface 181.In a preferred embodiment, the sheath 147 is formed of an elastomer,such as neoprene, so its frustule conical and cylindrical configurationsexist primarily in the natural unstretched state.

As the sheath 147 is stretched axially, the diameter of the cylindricalproximal end increases thereby placing radial forces on the incision 32.The more the sheath 147 is stretched axially, the greater becomes thediameter of the sheath and consequently the larger becomes the openingthrough the incision 32. This feature is of particular advantage as itpermits the surgeon to define the size of the incision 32 with anappropriate degree of axial tension on the sheath 147. By maintainingthis tension, the preferred size of the incision 132 is maintainedthroughout the operation. In a preferred apparatus and method, the axialtension is maintained by stretching the sheath 147 over the tabs 167(FIG. 34) of the base 145. Indicia 182 can be printed on the sheath 147to provide an indication of the relationship between the axial stretchof the sheath 147 and the size of the incision 32.

The fold 153 is provided to facilitate a grip on the proximal end of thesheath 147. This fold 153 can also function to provide reinforcementwhere the walls of the sheath 147 engage the tabs 167 of the base 145.In the embodiment illustrated in FIG. 38 additional folds 184, 186 areprovided at spaced axial locations, such as those defined by the indicia182 in FIG. 37. With these folds 184 and 186, additional points ofreinforcement are provided to engage the tabs 167 while providing thesheath 147 with predetermined degrees of axial stretch associated withdifferent sizes of the incision 32.

The method of using the embodiment of FIG. 32 is illustrated theprogressive use of FIGS. 39-42. In FIG. 39, a top plan view of theabdominal wall 21 of the patient 10 is illustrated with a template 195positioned to facilitate location of the incision 32. The size of theincision 32 can be determined with the indicia 182 on the template 195showing, for example, multiple lengths of a line 197, each length beingequated with a glove size for the surgeon's hand 17 (FIG. 7). Knowinghis/her glove size, the surgeon will merely cut the incision inaccordance with an appropriate length of the line 197. The longerlengths of the line 197 are associated with the larger incisions, thelarger glove sizes and accordingly the larger hands 17. After theincision 32 has been cut along the line 197, the template 195 can beremoved.

As illustrated in FIG. 40, the retraction sheath 147 can then be mountedthrough the incision 32. Initially the ring 152 is compressed and fedthrough the incision 32. On the inner surface of the abdominal wall 21,the ring 152 is free to expand to its larger diameter, as shown by adotted line 158 in FIG. 40. The portions of the wall 176 which definethe cylinder 177 are left to extend proximally through the opening 32 asshown in FIG. 40.

Prior to or after inserting the sheath 147, the base 145 can be disposedaround the incision 32. Then the exposed portions of the sheath 147 willextend through the incision 32 and within the circumferential base 145.As illustrated in FIG. 41, the wall 176 of the sheath 147 can then bedrawn proximally, outwardly of the page in FIG. 41, to axially stretchthe sheath 147. As noted, when the sheath 147 is axially stretched, itwill create radial forces on the abdominal wall 21 which will tend toenlarge the incision 32. The greater the axial stretch, the larger theincision 32.

When the incision 32 has the desired size, the stretched sheath 147 canbe drawn over the tabs 167 to maintain the axial stretch and the desiredsize for the incision 32. Either the indicia 182, as shown in FIG. 36,or the additional folds 184 and 186 as shown in FIG. 37, can be alignedwith the tabs 167 to provide a predetermined size for the incision 32.At this point, the seal between the abdominal wall 21, the sheath 147,and the base 145 is fully established.

A final step remaining in this process is the attachment of the gel cap143 to the base 145. This is accomplished as illustrated in FIG. 36 bycapturing the lip 172 of the base 145 in the annular void 158 of the gelcap 143. Bending the holding tabs 156 upwardly and outwardly facilitatesthis engagement which ultimately forms a seal between the base 145 andthe gel cap 143.

Although this invention has been disclosed with reference to certainstructural configurations, it will be appreciated that these productsare merely representative of many different embodiments of theinvention. Accordingly, one is cautioned not to limit the concept onlyto the disclosed embodiments, but rather encouraged to determine thescope of the invention only with reference to the following claims.

1. A surgical access device adapted for performing laparoscopic surgicalprocedures with at least one instrument passing through the surgicalaccess device and through a single incision in the abdominal wall of apatient with the abdominal cavity pressurized with an insufflation gas,the surgical access device adapted to provide instrument access to theabdominal cavity for surgical procedures while generally maintaininginsufflation pressure in the abdominal cavity, the surgical accessdevice comprising: an access pad, the access pad comprising a materialformed of a mixture comprising a triblock copolymer, an oil, and afoaming agent, the access pad adapted to be disposed within an incisionwithin an abdominal wall, the access pad having an external flange andan internal flange integrally formed with the access pad, the externalflange adapted to be disposed external to the abdominal wall in anoperative position and the internal flange adapted to be disposedinternal to the abdominal wall in the operative position, wherein theaccess pad is configured to be maintained in the operative position andadapted to form a seal with the abdominal wall; and at least one openingthrough the access pad between an external surface and an internalsurface of the access pad, wherein the opening when operatively disposedis in communication with the incision and forms a working channelbetween a location external to the abdominal wall and a locationinternal to the abdominal wall; wherein the access pad is adapted toconform to a surface of an instrument inserted through the workingchannel, at least a portion of the access pad between the externalflange and the internal flange and within the incision between anexternal surface of the abdominal wall and an internal surface of theabdominal wall is adapted to form an instrument seal with theinstrument, and wherein locating the access pad within the incisioncreates a radially compressive force to provide an axial seal betweenthe access pad and the abdominal wall.
 2. The surgical access device ofclaim 1, further comprising a plurality of trocars configured forplacement through a plurality of openings.
 3. The surgical access deviceof claim 1, wherein the at least one opening accommodates a range ofinstrument diameters.
 4. The surgical access device of claim 1, whereinthe access pad is adapted for direct contact with the abdominal wallduring use.
 5. The surgical access device of claim 1, wherein the accesspad is adapted for direct contact with a plurality of instruments duringuse.
 6. The surgical access device of claim 1, wherein at least aportion of the external surface is curved.
 7. The surgical access deviceof claim 1, wherein the material is formed of a mixture consistingessentially of a triblock copolymer, an oil, and a foaming agent.
 8. Thesurgical access device of claim 1, wherein the triblock copolymercomprises a Styrene-Ethylene/Butylene-Styrene structure.
 9. A surgicalaccess device adapted for performing laparoscopic surgical procedureswith multiple instruments passing through the surgical access device andthrough a single incision in the abdominal wall of a patient with theabdominal cavity pressurized with an insufflation gas, the surgicalaccess device adapted to provide instrument access to the abdominalcavity for surgical procedures while generally maintaining insufflationpressure in the abdominal cavity, the surgical access device comprising:an access seal, the access seal adapted to be disposed within anincision within an abdominal wall, the access seal having an externalflange and an internal flange, the external flange adapted to bedisposed external to the abdominal wall in an operative position and theinternal flange adapted to be disposed internal to the abdominal wall inthe operative position, wherein the access seal is configured to bemaintained in the operative position; and a plurality of access channelsthrough the access seal between an external surface and an internalsurface of the access seal, wherein the plurality of access channelswhen operatively disposed span the thickness of the abdominal wall andform working channels between a location external to the abdominal walland a location internal to the abdominal wall; the access seal beingformed of an elastomeric material adapted to conform to a surface of aninstrument inserted through the working channel to form an instrumentseal along a length substantially spanning the thickness of theabdominal wall and the elastomeric material in the operative position isadapted to form an abdominal seal within the abdominal wall.
 10. Thesurgical access device of claim 9, wherein the elastomeric material ofthe access seal is configured to substantially fill the volumesurrounding the plurality of access channels and spanning the thicknessof the abdominal wall within the incision.
 11. The surgical accessdevice of claim 9, wherein the access seal is adapted to maintain asealing relationship with a plurality of instruments positioned throughthe access seal while accommodating relative movement between theplurality of instruments.
 12. The surgical access device of claim 9,wherein at least one of the plurality of access channels is configuredto self seal in the absence of any instrument extending through the atleast one access channel.
 13. The surgical access device of claim 9,wherein the elastomeric material is a thermoplastic elastomer.
 14. Thesurgical access device of claim 9, wherein the elastomeric material isformed of a material comprising at least one of a triblock copolymer, adiblock copolymer, an oil, a foam, silicone, a polyurethane, PVC, andisoprene.
 15. The surgical access device of claim 9, wherein theelastomeric material is formed of a mixture comprising a triblockcopolymer that has a Styrene-Ethylene/Butylene-Styrene structure. 16.The surgical access device of claim 9, wherein the elastomeric materialis formed of a mixture comprising a triblock copolymer, an oil, and afoaming agent.
 17. The surgical access device of claim 9, wherein theelastomeric material is formed of a mixture consisting essentially of atriblock copolymer, an oil, and a foaming agent.
 18. The surgical accessdevice of claim 9, wherein each of the plurality of access channels hasa cross-sectional dimension along the length substantially spanning thethickness of the abdominal wall, and wherein the cross-sectionaldimension is less than or equal to a cross-sectional dimension of eachof a plurality of instruments that are adapted to be positioned throughthe plurality of access channels.
 19. A method of using a surgicalaccess device adapted for performing laparoscopic surgical procedureswith at least one instrument passing through the surgical access deviceand through a single incision in the abdominal wall of a patient withthe abdominal cavity pressurized with an insufflation gas, the surgicalaccess device adapted to provide instrument access to the abdominalcavity for surgical procedures while generally maintaining insufflationpressure in the abdominal cavity, the method comprising: providing anaccess seal, the access seal having an external flange, an internalflange, and at least one access channel through the access seal betweenan external surface and an internal surface of the access seal, theaccess seal being formed of an elastomeric material; disposing theaccess seal within an incision within an abdominal wall such that theexternal flange is disposed external to the abdominal wall in anoperative position, the internal flange is disposed internal to theabdominal wall in the operative position, and the access channel spansthe thickness of the abdominal wall and forms a working channel betweena location external to the abdominal wall and a location internal to theabdominal wall in the operative position, wherein locating the accesspad within the incision creates a radially compressive force to providean axial seal between the access pad and the abdominal wall such thatthe elastomeric material in the operative position forms the axial sealwithin the abdominal wall; and inserting at least one instrument throughthe working channel, wherein at least a portion of the access padbetween the external flange and the internal flange and within theincision between an external surface of the abdominal wall and aninternal surface of the abdominal wall forms an instrument seal with theinstrument, the elastomeric material conforms to a surface of theinstrument inserted through the working channel to form the instrumentseal along a length substantially spanning the thickness of theabdominal wall.
 20. The method of claim 19, wherein the elastomericmaterial of the access seal is formed of a mixture comprising a triblockcopolymer and the elastomeric material substantially fills the volumesurrounding a plurality of access channels and spans the thickness ofthe abdominal wall within the incision.